Improvement in artificial arms



IINITED STATES;

PATENT FFICE.

IMPROVEMENT IN ARTIFICIAL ARMS.

Specification forming part of Letters Patent No. 42,515, dated April 26,1864.

figures and letters of reference marked thereon.

"My invention consists, mainly, in an improved method of actuating thefingers and thumb, whereby the grasping and holding of objects andrelease of the same, are accomplished in a more natural and perfect manner than by any of the movements and mechanism heretofore employed. Inartificial arms of various construction now in use the opening movementof the hand is obtained by stretching the arm from the body and throwingthe shoulder-blade into a peculiar position, requiring great effort andan unnatural position of the upper body, whereupon a forward leaning ofthe body and return of the shoulder to its natural position are requiredto allow the hand to close.

WVith the use of my improved mechanism, however, the opening of the handis derived froma pressure of the upper arm against the side of thechest, while the release of this pressure closes the hand.

Another important feature of my invention consists in the employment ofa peculiar de-e vice at the elbow-joint for transmitting the movementsto the hand, said device being so arranged as to actuate the hand in anyposition of the elbow-joint, from a straight extension of the arm toextreme upward bending of the forearm.

That portion of the improved mechanism which, by pressure against theside of the body, actuates the hand is so contrived as to enable thewearer of the limb to throw it instantly out of action whenever he doesnot require the use of the artificial hand. By so doing the above partsare so diminished in bulk as to lie close against the upper arm, thuscausing not the slightest inconvenience to the wearer. The throwingintoaction of the hand mechanism is also readily efi'ected at any moment itmay be required.

In order that my said invention may be fully understood, I will nowproceed more particularly to describe the construction and operation ofthe same. 1

On reference to the drawings making part of this specification, and inwhich similar letters of reference allude to like parts in the severalviews, Figure 1 is a side view of an artificial arm of my improvedconstruction, partly drawn in section. Fig. 2 is a plan of the same,also represented partly in section, the pressure pad and mechanism beingin this view represented in the position they occupy when the fingersare closed. Fig. 3 exhibits the pressure-pad and its mechanism in theirposition when the hand is opened by the pressure of the pad against theside of the body. In Fig. 4 the pad and its mechanism are shown in theirdisconnected condition.

Fig. 5 is a view of the elbow-joint in an extended position, the devicefor transmitting movement from the pad to the hand mechanism beingrepresented in extreme positions in red and black lines. F ig. 6 is asimilar view of the same parts, representing their action in acontracted position of the elbow-joint.

The artificial arm represented in the drawings is of the constructionemployed when the limb has been amputated below the elbow, the hollowsocket-shaped lower arm, A, serving to receive the stump remaining belowthe stood that my improvement is equally well adapted where the arm hasbeen amputated immediately above or at the elbow. In such cases theusual appliances for retaining the elbow-joint in any required positionare added, while the devices for actuating the hand remain the same asshown and hereinafter described. The lower arm, A, which may be formedof leather, india-rubber, or any of the usual materials, is providedwith a metallic band or elbow piece, B, to which are jointed at a a thesteel strips (3 0. These strips are united by elastic semicircular steelbands D D, which bands carry with the strips 0 the leather clasp E, thelatter adjusting itself to the size and shape of the stump, and servingto secure the artificial arm thereto by means of its buckle-straps I) b.The pressure-pad is so placed on the inner side of the arm as to restagainst the side of the body, and consists of two thin metallic plates,F F", hinged together at c, and covered by a leathercushion, Gr. To theplate F of the pad two'forward-extending arms, dd, are attached, whichare hinged to the strip 0 at e e. Beneath the padare two links, H and K,jointed at f, of which the former vibrates upon fulcrum-pins g g in C,while K is hinged at h to a slide, L,

elbow. It will, however, be readily underresting upon the strip 0 andguided at its sides by being confined between lugs at the joints 0 e andg g. Upon reference to Figs. 2, 3, and 4 the relative position of theseparts and the manner in which the links H and K and the slide L areactuated by the pressurepad will be readily understood, 0 e-being thepermanent fulcrums of a knee-joint formed by the arms H and K. Thesearms wi 1, upon a depression of the pad, draw the slide L. upward. (SeeFig. 3.) This slide L then, by means of intermediate connections,(hereinafter fully described,) actuates the mechanism of the hand. Thearrangement of the fingerjoints and of the levers and links in immediateconnection therewith and contained in the interior of the hand are not apart of my invention, as they are substantially similar to those alreadyin common use, and will, therefore, (as they are, moreover, clearlyshown in Figs. 1 and 2 of the drawings,) not require a more minutedescription here than is requisite in explaining the operation of myimprovements.

The slide L is at its forward end provided with a socket, h, for thereception of a flat rod or link, i, resting beyond the socket upon theouter flat surface of L. This rod z' is atj jointed to another shorterlink, k, the forward end of which extends to the elbow-joint, and ishere hinged at a; to a bell-crank, M. This bell-crank has its fulcrumupon pins 1, resting in slotted holes on in the elbow-piece B of theforearm, and has at its third joint, a, a forward'extending flat rod, 0,attached, which at its other extremity connects with a vibrating arm, p,having its fulcrum at q. When by I depression of the pad the rod 0 isthrough the described intermediate connections pulled in the directionof its arrow, (see Fig. 1,) it so actuates through the arm 19 themechanism of the hand as to straighten out the thumb and fingers andseparating them for g1 asping an object. In this open position the handcontinues aslon gas thepadremains depressed. I As soon, however, as thepressure ceases, by moving the upper arm slightly outward from the side,the rod 0 and all its connections are by the tension of spiral springs Nand Q moved in the opposite direction to that indicated by the arrow in,Fig. 1, the fingers being thus eontracted and the pad elevated to theposition shown at Fig. 2. To the socket h of slide L ,i: attached asmall latch, r, whii-h is provided with a locking-pin, s, passingthrough the top of the sorket and entering ahole of corresponding sizein the rodt',this rod being thus secured to the slide L and made totransmitthe sliding movement of thelatter, as above described. Todisengage the pressure-pad, for the purpose of diminishing its bulk whenthe hand mechanism is not required, the wearer has simply'to depresswith his remaining hand the tail-piece 2 of the latch 1", and sodisconnect the rod '5 from the slide L by withdrawing the pin 8 from itshold in rod 1'. This rod.

ihen remains in the position in which it is ,crumpins l l are carriedback and forward in Y to secure by Letters Patent, is-

held by its connection with the hand mechanism, while the slide L, beingdetached from it, will yield to the depression of the pad until thelinks H and K are straightened out and rest upon L. (See Fig. 4.) Thepad, being thus permitted to lie close against the arm, will not in theleast inconvenience the wearer at times when he does not require the useof the hand mechanism. To throw the pad and its connections into action,the wearer has but to press against the upper end of slide L, so as topush it forward until the locking-pin s of latch 1 takes hold of .therod 1', the position of arms H and K and pressure-pad being therebychanged to that shown in Fig. 2.

The manner in which the reciprocating movement of slide L and rod 0 istransmitted by the bell-crank M alternately from one to the other at anyposition of the elbow'joint will be readily understood upon reference toFigs. 5 and 6. As long as the forearm is extended or forming an obtuseangle with the upper arm, (as drawn at Fig. 5,) the bell-crank M acts asa plain link-connection, and its fulthe slots m of the elbow-piece B.When, however, the position of the arm is changed to an acute angle, (asin Fig. 6,) the position of the slots m in B is so altered in relationto the line of motion of link 70 and its upward connect-ions as to causethe bell crank M to vibrate on its fulcrum-pins 1 without sliding in theslots m. At certain intermediate positions of the arm between theextremes shown the action of the bell-crank M becomes divided between apartial sliding of its pins lin the slot m and a radial movement of thesame. Having thus described the nature of m invention and theconstruction and operation of the parts constituting the same, I wish tobe understood as not desiring to limit mysel to the describedcombination and arrange ment of the parts in every minutia; but

What I claim as my invention, and desir 1. The described method ofactuating th hand mechanism by a pressure-pad attache to the inner sideof the arm beneath th shoulder-joint, and deriving its action froipressure of the upper arm against the side substantially as and for thepurpose specified 2. The employment of a bell-crank, M, a theelbow-joint for transmitting motion fro the pad to the hand mechanism,and vice versa the fulcrum pin or pins 1 of said beltcrah being confinedin slots m in the elbow-piec B, the whole operating substantially in thmanner and for the purpose set forth.

3. Disconnectin g the pressure-pad from th hand mechanism by means ofthe latch r, op erating as described, or in any manner equiv alentthereto, for the purpose set forth.

EDWARD SPELLERBERG.

Witnesses:

VALENTIN SoHnK, THEODORE BERGNER.

